Anti-fatigue composition

ABSTRACT

Compositions and foods which contain (1) histidine and (2) vitamin B6 and/or carnosine are useful for treating, improving, and recovering from fatigue.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/JP2014/076989, filed on Oct. 8, 2014, and claims priority toJapanese Patent Application No. 2013-212329, filed on Oct. 9, 2013, bothof which are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to anti-fatigue compositions, foods whichcontain such a composition, and uses of such a composition.

Discussion of the Background

Histidine is one kind of basic amino acid, and is an essential aminoacid having an imidazoyl group as a heteroaromatic ring in the sidechain. Histidine is an amino acid admitted as a food additive, andcontained in many foods. For example, histidine is added as a seasoningor flavor-adjusting agent aiming at firm taste, prevention of diffusionof flavor, and the like, and the content thereof is about 50 mg/100 mlat maximum. In relation to the known function of histidine, ananti-fatigue composition containing histidine or histidine hydrochlorideis known (see JP-A-2006-137706, which is incorporated herein byreference in its entirety).

Vitamin B6 is one kind of water-soluble vitamin and is a pyridinederivative. Vitamin B6 includes pyridoxine, pyridoxal and pyridoxamine,and they are mutually convertible. They are phosphorylated in the bodyinto pyridoxal 5′-phosphate (PLP) and pyridoxamine 5′-phosphoate, andfunction as a coenzyme of an enzyme involved in amino acid metabolismsuch as transamination reaction, decarboxylation reaction and the like.They are also necessary for a reaction to biosynthesize niacin fromtryptophan as amino acid, a reaction to biosynthesize glucose1-phosphate from glycogen, and a reaction to synthesize dopamine andy-aminobutyric acid as neurotransmitters.

In 2010, vitamin B6 was determined to have the following functions inthe “functional claims for food and supplement” issued by EFSA (EuropeanFood Safety Authority) (see EFSA Journal 2010; 8(10):1759, which isincorporated herein by reference in its entirety). Normal homocysteinemetabolism, maintenance of normal bones/tooth/hair/skin/nail, normalenergy-yielding and metabolism, normal psychological function, reductionof tiredness and fatigue, normal cysteine synthesis.

Carnosine is a dipeptide wherein histidine and β alanine are bonded, andis contained in animal-derived foods in large amounts. Carnosine ismainly present in muscles and brain, and a buffering action, anantioxidation action and the like are known (see Amino san no kagaku tosaishin ouyou gijiyutsu p. 272-282 CMC Publishing Co., Ltd. 2008, whichis incorporated herein by reference in its entirety). It has also beenreported that imidazole dipeptide which is a mixture of carnosine andanserine (dipeptide wherein 1 methylhistidine and β alanine are bonded)shows an anti-fatigue effect (see Journal of Clinical and ExperimentalMedicine, vol. 228, No. 6, p. 722-726, 2009, which is incorporatedherein by reference in its entirety).

However, there remains a need for improved anti-fatigue compositions.

SUMMARY OF THE INVENTION

Accordingly, it is one object of the present invention to provide novelanti-fatigue compositions.

It is another object of the present invention to provide novel foodswhich contain such an anti-fatigue composition.

It is another object of the present invention to provide novel methodsof treating and/or preventing fatigue.

When amino acid is added to a food and the like, an influence of thedistinct taste of amino acid needs to be considered in some occasions.While histidine is known to have an anti-fatigue effect, since histidinealso has a sour taste and a bitter taste, the amount thereof to be addedto foods tends to be limited, which sometimes prevents exhibition of asufficient anti-fatigue action. Therefore, the present invention aims toprovide a histidine-containing food capable of affording a sufficientanti-fatigue effect even at a low histidine content, and the like.

These and other objects, which will become apparent during the followingdetailed description, have been achieved by the inventors' discoverythat fatigue can be more effectively improved by using histidine incombination with vitamin B6 and/or carnosine, particularly that afatigue-improving effect can be obtained even at a low dose at which asingle use of each of them cannot provide an effect. Thus, the presentinvention provides:

(1) An anti-fatigue composition, comprising (1) histidine and (2)vitamin B6 and/or carnosine in combination.

(1-1) A method of improving fatigue, comprising administering (1) aneffective amount of histidine and (2) an effective amount of vitamin B6and/or carnosine to a subject in need thereof.

(1-2) A composition for improving fatigue, comprising (1) histidine and(2) vitamin B6 and/or carnosine in combination.

(2) The composition of the above-mentioned (1), comprising histidine andvitamin B6 in combination.

(2-1) A method of improving fatigue, comprising administering aneffective amount of histidine and an effective amount of vitamin B6 to asubject in need thereof.

(2-2) A composition for improving fatigue, comprising histidine andvitamin B6 in combination.

(3) The composition of the above-mentioned (1), comprising histidine andcarnosine in combination.

(3-1) A method of improving fatigue, comprising administering aneffective amount of histidine and an effective amount of carnosine to asubject in need thereof.

(3-2) A composition for improving fatigue, comprising histidine andcarnosine in combination.

(4) The composition of the above-mentioned (2), wherein thehistidine:vitamin B6 is 5:3-350:1.

(4-1) The method of the above-mentioned (2-1), wherein thehistidine:vitamin B6 is 5:3 to 350:1.

(4-2) The composition of the above-mentioned (2-2), wherein thehistidine:vitamin B6 is 5:3 to 350:1.

(5) The composition of the above-mentioned (4), wherein the histidine iscontained at not less than 0.3 g per unit package.

(5-2) The composition of the above-mentioned (4-2), wherein thehistidine is contained at not less than 0.3 g per unit package.

(6) The composition of the above-mentioned (4) or (5), wherein thehistidine is contained at not less than 0.3 g as an ingestion amount permeal.

(6-2) The composition of the above-mentioned (4-2) or (5-2), wherein thehistidine is contained at not less than 0.3 g as an ingestion amount permeal.

(7) The composition of any of the above-mentioned (4)-(6), wherein thevitamin B6 is contained at not less than 0.5 mg as an ingestion amountper meal.

(7-2) The composition of any of the above-mentioned (4-2), (5-2) and(6-2), wherein the vitamin B6 is contained at not less than 0.5 mg as aningestion amount per meal.

(8) The composition of the above-mentioned (3), whereinhistidine:carnosine is 1:4 to 100:1.

(8-2) The composition of the above-mentioned (3-2), whereinhistidine:carnosine is 1:4 to 100:1.

(9) A container-packed food, comprising (1) histidine and (2) vitamin B6and/or carnosine.

(10) The container-packed food of the above-mentioned (9), comprisinghistidine and vitamin B6.

(11) The container-packed food of the above-mentioned (9), comprisinghistidine and carnosine.

(12) The container-packed food of the above-mentioned (10), whereinhistidine:vitamin B6 is 5:3 to 350:1.

(13) The container-packed food of the above-mentioned (12), wherein thehistidine is contained at not less than 0.3 g as an ingestion amount permeal.

(14) The container-packed food of the above-mentioned (12) or (13),wherein the vitamin B6 is contained at not less than 0.5 mg as aningestion amount per meal.

(15) The container-packed food of any of the above-mentioned (9)-(14),further comprising at least one kind of additive selected fromexcipient, corrigent and flavor.

(16) The container-packed food of any of the above-mentioned (9)-(15),which is in the form of a solid, semi-solid or liquid.

(17) The container-packed food of any of the above-mentioned (9)-(15),which is in the form of powder, tablet, granule or capsule.

(18) The container-packed food of any of the above-mentioned (9)-(15),which is in the form of slurry, solution, jelly or emulsion.

(19) The container-packed food of any of the above-mentioned (9)-(18),which is in a unit package form per meal.

(20) The container-packed food of any of the above-mentioned (9)-(19),which is for improving fatigue.

(21) A food comprising (1) histidine and (2) vitamin B6 and/orcarnosine, which is in a unit package form per meal.

(22) The food of the above-mentioned (21) comprising histidine andvitamin B6, which is in a unit package form per meal.

(23) The food of the above-mentioned (21) comprising histidine andcarnosine, which is in a unit package form per meal.

(24) The food of the above-mentioned (22), wherein histidine:vitamin B6is 5:3 to 350:1.

(25) The food of the above-mentioned (24), wherein histidine iscontained at not less than 0.3 g.

(26) The food of the above-mentioned (24) or (25), wherein vitamin B6 iscontained at not less than 0.5 mg. (27) The food of the above-mentioned(23), wherein histidine:carnosine is 1:4 to 100:1.

(28) The food of the above-mentioned (27), wherein histidine iscontained at not less than 0.3 g.

(29) The food of any of the above-mentioned (21)-(28), furthercomprising at least one kind of additive selected from excipient,corrigent and flavor.

(30) The food of any of the above-mentioned (21)-(29), which is in theform of a solid, semi-solid or liquid.

(31) The food of any of the above-mentioned (21)-(29), which is in theform of powder, tablet, granule or capsule.

(32) The food of any of the above-mentioned (21)-(29), which is in theform of slurry, solution, jelly or emulsion.

(33) The food of any of the above-mentioned (21)-(32), which is a foodwith health claims.

(34) The food of any of the above-mentioned (21)-(33), which is forimproving fatigue.

(35) A container-packed drink comprising (1) histidine and (2) vitaminB6 and/or carnosine.

(36) The container-packed drink of the above-mentioned (35), comprisinghistidine and vitamin B6.

(37) The container-packed drink of the above-mentioned (35), comprisinghistidine and carnosine.

(38) The container-packed drink of the above-mentioned (36), whereinhistidine:vitamin B6 is 5:3 to 350:1.

(39) The container-packed drink of the above-mentioned (38), whereinhistidine is contained at not less than 0.3 g as an ingestion amount permeal.

(40) The container-packed drink of the above-mentioned (38), whereinhistidine is contained at not less than 1 w/v%.

(41) The container-packed drink of any of the above-mentioned (38)-(40),wherein vitamin B6 is contained at not less than 0.5 mg as an ingestionamount per meal.

(42) The container-packed drink of any of the above-mentioned (35)-(41),which is in a unit package form per meal.

(43) The container-packed drink of any of the above-mentioned (35)-(42),which is a food with health claims.

(44) The container-packed drink of any of the above-mentioned (35)-(43),which is for improving fatigue.

Effect of the Invention

Fatigue (mental fatigue, physical fatigue) can be improved by ingestingthe composition of the present invention, comprising (1) histidine and(2) vitamin B6 and/or carnosine. Since the present invention containsamino acid (peptide) and vitamin as active ingredients, it has less fearof causing side effects and is superior in safety, and can also beconsecutively used everyday.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same become betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG 1A shows the protocol of generating a fatigue model by burden ofinsufficient sleep, for the measurement of locomotor activities in thedark phase.

FIG. 1B shows cumulative locomotor activities for the former half (6 hr)of the dark phase. *: t-test, p<0.05.

FIG. 2A shows the protocol for generating a fatigue model by burden ofinsufficient sleep, for the measurement of short-working memory.

FIG. 2B shows the measurement results of alternation behavior. ***:t-test, p<0.001.

FIG. 3A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or test substance X on the improvement of a decreasein the locomotor activities in the dark phase (fatigue index) of mouseafter burden of insufficient sleep.

FIG. 3B shows cumulative locomotor activities for the former half (6 hr)of the dark phase when histidine (His) and/or vitamin B6 (VB6) are used.*: Tukey's multiple test, p<0.05. †t: Tukey's multiple test, p<0.1.

FIG. 3C shows cumulative locomotor activities for the former half (6 hr)of the dark phase when histidine (His) and/or carnosine are used. *:Tukey's multiple test, p<0.05.

FIG. 4A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or vitamin B6 (VB6) on the change of short-workingmemory (fatigue index) of mouse after burden of insufficient sleep.

FIG. 4B shows the measurement results of alternation behavior. **:Tukey's multiple test, p<0.01. *: Tukey's multiple test, p<0.05.

FIG. 5A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or vitamin B6 (VB6) (His:VB6=120:1) on the change ofshort-working memory (fatigue index) of mouse after burden ofinsufficient sleep.

FIG. 5B shows the measurement results of alternation behavior. **:Tukey's multiple test, p<0.01. *: Tukey's multiple test, p<0.05.

FIG. 6A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or vitamin B6 (VB6) (His:VB6=120:1) on the change oflocomotor activities (fatigue index) of mouse after burden ofinsufficient sleep.

FIG. 6B shows the measurement results of locomotor activities in thedark phase. *: Tukey's multiple test, p<0.05 vs VB6 group. #: Tukey'smultiple test, p<0.05 vs solvent group. †t: Tukey's multiple test, p<0.1vs solvent group. ‡: Tukey's multiple test, p<0.1 vs His group. §:Tukey's multiple test, p<0.1 vs VB6 group.

FIG. 6C shows the measurement results of locomotor activities in 4 hr to5 hr after the start of the dark phase. #: Tukey's multiple test, p<0.05vs solvent group. ‡: Tukey's multiple test, p<0.1 vs His group. §:Tukey's multiple test, p<0.1 vs VB6 group.

FIG. 7A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or vitamin B6 (VB6) (His:VB6=360:1) on the change ofshort-working memory (fatigue index) of mouse after burden ofinsufficient sleep.

FIG. 7B shows the measurement results of alternation behavior. *:Tukey's multiple test, p<0.05.

FIG. 8A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or vitamin B6 (VB6) (His:VB6=360:1) on the change oflocomotor activities (fatigue index) of mouse after burden ofinsufficient sleep.

FIG. 8B shows the measurement results of locomotor activities in thedark phase.

FIG. 9A shows the protocol for verifying the anti-fatigue effect ofhistidine (His) ingestion in test subjects feeling fatigue and adecrease in the quality of sleep.

FIG. 9B shows variation of T scores in POMS. *: paired t-test, p<0.05.

FIG. 9C shows variation of each index in VAS before cognitivefunctioning test (CogHealth). *: paired t-test, p<0.05.

FIG. 9D shows variation in the reaction time in cognitive functioningtest. *: paired t-test, p<0.05.

FIG. 9E shows variation of each index in VAS after cognitive functioningtest. *: paired t-test, p<0.05.

FIG. 10A shows the protocol for verifying the anti-fatigue effect ofsingle histidine (His) ingestion in test subjects feeling fatigue and adecrease in the quality of sleep.

FIG. 10B shows variation of each index in VAS before cognitivefunctioning test (CogHealth). *: paired t-test, p<0.05.

FIG. 10C shows variation of each index in VAS after cognitivefunctioning test. *: paired t-test, p<0.05.

FIG. 11A shows the protocol for verifying the effect of the ingestion ofhistidine (His) and/or vitamin B6 (VB6) (His:VB6=300:1) on the change ofshort-working memory (fatigue index) of mouse after burden ofinsufficient sleep.

FIG. 11B shows the measurement results of alternation behavior. *:Tukey's multiple test, p<0.05.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The mode of embodiment of the present invention is explained below.

In the present invention, histidine is an essential amino acid havingthe following structural formula.

The histidine used in the present invention may be a substanceconvertible to histidine by hydrolysis. The “substance convertible tohistidine by hydrolysis” is a substance that affords histidine byhydrolysis (particularly in vivo hydrolysis), and typical examplesthereof include proteins and peptides containing histidine as aconstituent unit. A substance that affords histidine by hydrolysisproduces histidine by hydrolysis in the body after ingestion, and isexpected to provide an effect similar to that obtained when histidine isingested from the start.

The histidine to be used in the present invention may be one extractedand purified from naturally-present animals, plants and the like, or oneobtained by a chemical synthesis method, a fermentation method, anenzyme method or a gene recombination method. Any of L-form, D-form, andDL-form can be used. A commercially available one can be utilized and ispreferable since it is convenient.

Vitamin B6 is one kind of water-soluble vitamin having the followingstructure.

Vitamin B6 includes pyridoxine, pyridoxal, and pyridoxamine, which aremutually convertible. While the vitamin B6 used in the present inventionmay be any compound as long as a desired effect can be exhibited, it ispreferably pyridoxine.

The vitamin B6 to be used in the present invention may be one extractedand purified from naturally-present animals, plants and the like, or oneobtained by a chemical synthesis method. A commercially available onecan be utilized and is preferable since it is convenient.

Carnosine is a dipeptide having the following structure, whereinhistidine and β alanine are bonded.

The carnosine to be used in the present invention may be one extractedand purified from naturally-present animals, plants and the like, or oneobtained by a chemical synthesis method, a fermentation method, anenzyme method or a gene recombination method. While L-form and D-form(naturally L-form alone) are present due to stereoisomerism, any of themcan be used. A commercially available one can be utilized and ispreferable since it is convenient.

The carnosine used in the present invention may be a substanceconvertible to carnosine by hydrolysis. The “substance convertible tocarnosine by hydrolysis” is a substance that affords carnosine byhydrolysis (particularly in vivo hydrolysis), and typical examplesthereof include proteins and peptides containing carnosine as aconstituent unit. A substance that affords carnosine by hydrolysisproduces carnosine by hydrolysis in the body after ingestion, and isexpected to provide an effect similar to that obtained when carnosine isingested from the start.

In the present specification, when histidine per se is used as thehistidine, the content of histidine in a composition or food isdetermined taking note of the weight of histidine and, when a substanceconvertible to histidine by hydrolysis is used, by converting tohistidine. When a composition or food contains both histidine and asubstance convertible to histidine by hydrolysis, the content ofhistidine in the composition or food is the total weight of the weightof histidine obtained by converting, by hydrolysis, all substancesconvertible to histidine by hydrolysis, and histidine presented from thestart.

Similarly, when carnosine per se is used as the carnosine, the contentof carnosine in a composition or food is determined taking note of theweight of carnosine and, when a substance convertible to carnosine byhydrolysis is used, by converting to carnosine. When a composition orfood contains both carnosine and a substance convertible to carnosine byhydrolysis, the content of carnosine in the composition or food is thetotal weight of the weight of carnosine obtained by converting, byhydrolysis, all substances convertible to carnosine by hydrolysis, andcarnosine presented from the start.

Histidine (or substance convertible to histidine by hydrolysis), vitaminB6, and carnosine (or substance convertible to carnosine by hydrolysis)used in the present invention may be in the form of a salt. The form ofthe salt may be, for example, acid addition salt, salt with a base andthe like, and pharmacologically acceptable salt is preferable. Examplesof such salt include salts with inorganic acids, salts with organicacids, salts with inorganic bases, and salts with organic bases.

Examples of the salt with an inorganic acid include salts withhydrohalic acid (hydrochloric acid, hydrobromic acid, hydroiodic acidetc.), sulfuric acid, nitric acid, phosphoric acid, and the like.

Examples of the salt with an organic acid include salts with formicacid, acetic acid, propionic acid, oxalic acid, succinic acid, maleicacid, fumaric acid, citric acid, and the like.

Examples of the salt with an inorganic base include salts with alkalimetals such as sodium, potassium, lithium and the like, salts withalkaline earth metals such as calcium, magnesium and the like, salt withammonium and the like.

Examples of the salt with an organic base include salts withethylenediamine, propylenediamine, ethanolamine, monoalkylethanolamine,dialkylethanolamine, diethanolamine, triethanolamine and the like.

In the present specification, histidine, “substance convertible tohistidine by hydrolysis” and a salt thereof are hereinafter genericallyreferred to as histidine, and carnosine, “substance convertible tocarnosine by hydrolysis” and a salt thereof are hereinafter genericallyreferred to as carnosine.

One embodiment of the present invention is an anti-fatigue compositioncontaining (1) histidine and (2) vitamin B6/or carnosine in combinationand, particularly, an anti-fatigue composition containing histidine andvitamin B6 in combination, and an anti-fatigue composition containinghistidine and carnosine in combination are provided.

Another embodiment of the present invention is a method of improvingfatigue, comprising administering (1) an effective amount of histidine,and (2) vitamin B6 and/or an effective amount of carnosine to a subjectin need thereof and, particularly, a method of improving fatigue,comprising administering (1) an effective amount of histidine and (2) aneffective amount of vitamin B6 to a subject in need thereof, and amethod of improving fatigue, comprising administering (1) an effectiveamount of histidine, and (2) an effective amount of carnosine to asubject in need thereof are provided.

Another embodiment of the present invention is a composition containing(1) histidine and (2) vitamin B6 and/or carnosine in combination forimproving fatigue and, particularly, a composition containing histidineand vitamin B6 in combination for improving fatigue, and a compositioncontaining histidine and carnosine in combination for improving fatigueare provided.

The anti-fatigue composition, the method of improving fatigue, and thecomposition for improving fatigue of the present invention may usehistidine in combination with vitamin B6, histidine in combination withcarnosine, or histidine in combination with vitamin B6 and carnosine.Preferably, they use histidine in combination with vitamin B6. Thecombination ratio of histidine and vitamin B6 can be appropriatelydetermined within the range where an anti-fatigue effect can beobtained.

Preferable combination ratios include histidine:vitamin B6=5:3 to 350:1,15:1 to 350:1, 30:1 to 350:1, 60:1 to 350:1, and 90:1 to 350:1. Otherpreferable combination ratios include histidine:vitamin B6=5:3 to 350:1,5:3 to 300:1, 5:3 to 240:1, and 5:3 to 120:1. Still other preferablecombination ratios include histidine:vitamin B6=5:3 to 350:1, 15:1 to300:1, 30:1 to 240:1, 60:1 to 120:1, and 90:1 to 120:1.

The combination ratio of histidine and carnosine can also be determinedappropriately within the range where an anti-fatigue effect can beobtained.

Preferable combination ratios include histidine:carnosine =1:4 to 100:1,1:2 to 100:1, and 1:1 to 100:1. Other preferable combination ratiosinclude histidine:carnosine=1:4 to 100:1, 1:4 to 50:1, and 1:4 to 30:1.Other preferable combination ratios include histidine:carnosine=1:4 to100:1, 1:2 to 50:1, and 1:1 to 30:1.

When both vitamin B6 and carnosine are administered for combined usewith histidine, the dose of vitamin B6 and/or carnosine can be reducedas compared to a single administration thereof.

In the composition of the present invention, the administration form of(1) histidine and (2) vitamin B6/or carnosine is not particularlylimited, and (1) and (2) only need to be combined at the time ofadministration. Examples of such administration form include:

(A) administration as a single composition simultaneously containing (1)and (2),

(B) simultaneous administration of two kinds (or 3 kinds) ofcompositions separately containing (1) and (2) by the sameadministration route,

(C) administration of two kinds (or 3 kinds) of compositions separatelycontaining (1) and (2) by the same administration route in a staggeredmanner,

(D) simultaneous administration of two kinds (or 3 kinds) ofcompositions separately containing (1) and (2) by differentadministration routes,

(E) administration of two kinds (or 3 kinds) of compositions separatelycontaining (1) and (2) by different administration routes in a staggeredmanner and the like.

In 2010, the Japanese Society of Fatigue Science reported the definitionof “fatigue” as “fatigue is decline in the ability for activity of thebody accompanied by a peculiar sense of discomfort and a desire to rest,caused by excessive mental and psychological activities, or disease(s)”.

That is, “fatigue” is defined to be reduction of performance. In thepresent invention, “fatigue” is intended to mean both mental fatigue andphysical fatigue. The term “anti-fatigue” or “fatigue improvement”refers to a fatigue recovery action that promptly recovers the body fromthe state of fatigue, effect of relieving fatigue when physical burdenand mental burden (including burden of insufficient sleep and the like)are applied, or an action to relieve stresses felt daily such ascopiopia, mental fatigue, or mental insufficiency and the like, andfurther, improve efficiency of brain work.

The anti-fatigue composition of the present invention refers to acomposition that improves or recovers decline in the ability foractivity of the body accompanied by a peculiar sense of discomfort and adesire to rest, caused by excessive mental and psychological activities,or a disease.

The anti-fatigue effect can be evaluated by a method known per se.Examples of such methods include subjective evaluation methods such asvisual analog scale (VAS), Profile of Mood States (POMS) and the like,and objective evaluation methods such as cognitive functioning test.Coghealth (Coghealth: manufactured by Cogstate Ltd., Health Solution,Inc. provide) capable of measuring a brain function which will bedecreased due to fatigue and aging.

When VAS is utilized, for example, the level of fatigue can be judged byevaluating whether the test subject shows low scores of positive index(clear thinking, motivation, attentiveness or concentration), or highscore of negative index (depression or drowsiness). When, for example,scores are measured before and after continuous ingestion or singleingestion of a test sample for a given period, and the score of positiveindex significantly increases or the score of negative indexsignificantly decreases after sample ingestion, the fatigue can beevaluated to have been improved. Particularly, one or more indicesselected from the group consisting of clear thinking, motivation,attentiveness, concentration, depression and drowsinesscan can besignificantly improved by ingesting the composition of the presentinvention.

When POMS is utilized, for example, the level of fatigue can be judgedby evaluating whether the test subject shows low scores of positiveindex (vigor), or high score of negative index (anxiety, depression,anger, fatigue or confusion). More specifically, when the score offatigue factor (F factor) is not less than 16 by subjective evaluationby POMS, the presence of fatigue is admitted. When, for example, scoresare measured before and after continuous ingestion or single ingestionof a test sample for a given period, and the score of positive indexsignificantly increases or the score of negative index significantlydecreases after sample ingestion, the fatigue can be evaluated to havebeen improved. Particularly, the indices of fatigue and confusion can besignificantly improved by ingesting the composition of the presentinvention.

When CogHealth is utilized, for example, the level of fatigue can bejudged by evaluating whether the accuracy rate is low or the reactiontime is long in a simple reaction or delayed recall. Furthermore, forexample, when a test is performed after continuous ingestion of a testsample or placebo for a given period, and the accuracy ratesignificantly increases or the reaction time significantly decreases ina test sample ingestion group in a simple reaction or delayed recall ascompared to placebo ingestion group, the fatigue can be evaluated tohave been improved by ingesting the test sample. Particularly, thereaction time in the delayed recall can be significantly lowered byingesting the composition of the present invention.

For evaluation of fatigue and anti-fatigue in animals, a decrease inperformance and recovery of the decrease (change in locomotoractivities, alternation behavior showing short-working memory in thebelow-mentioned Y-maze test etc. as indices) only need to be measured bya method known per se, after applying a physical burden (treadmill,swimming etc.), mental burden (restraint stress etc.), or compositestress burden including both (insufficient sleep in water bed etc.). Forexample, a data acquisition analysis system containing an infraredsensor (e.g., NS-DAS-32 (NeuroScience, Inc) and the like) can beutilized. For example, measurement is performed after continuousingestion of a test sample or a control sample for a given period by atarget with fatigue induced by various burdens and, when a decrease inthe performance (decrease in spontaneous amount and alternationbehavior) is improved in a is test sample ingestion group as compared toa control sample ingestion group, the fatigue can be evaluated to havebeen improved/recovered by the ingestion of the test sample.

The anti-fatigue composition of the present invention may be solid orsemi-solid, or liquid such as powder, tablet, granule, capsule, slurry,solution, jelly, emulsion, and the like.

As one embodiment of the anti-fatigue composition of the presentinvention, a composition containing histidine:vitamin B6 at theabove-mentioned combination ratio, and histidine at not less than 0.3 g,preferably not less than 0.5 g, more preferably not less than 0.7 g,further preferably not less than 1 g, as an ingestion amount per meal isprovided. From the aspects of eating experiences obtained from knownfindings (Food Safety Commission of Japan, Feed/Fertilizer, etc. ExpertCommittee, April 2010, exempted evaluation report histidine, safety andeffectiveness information of “health food” (National Institute of Healthand Nutrition HP https://hfnet.nih.go.jp/) which is incorporated hereinby reference in its entirety) and easiness of packaging and ingestion,the ingestion amount per meal of histidine is preferably not more than23 g, more preferably not more than 4 g. In the present invention, sincethe effect of combined use of vitamin B6 on the anti-fatigue effect canbe expected, the ingestion amount per meal of histidine can be furtherreduced and, for example, an anti-fatigue composition containing notmore than 3 g, preferably not more than 2 g, of histidine as aningestion amount per meal can be provided.

In one embodiment of the anti-fatigue composition of the presentinvention, a composition containing histidine:vitamin B6 at theabove-mentioned combination ratio, and histidine at not less than 0.3 g,preferably not less than 0.5 g, more preferably not less than 0.7 g,further preferably not less than 1 g, per unit package is provided.Specifically, an anti-fatigue composition packaged as an ingestionamount per meal as one unit is provided.

In another embodiment of the anti-fatigue composition of the presentinvention, a composition containing histidine:vitamin B6 at theabove-mentioned combination ratio, and vitamin B6 at not less than 0.5mg, preferably not less than 2 mg, more preferably not less than 4 mg,further preferably not less than 6 mg, further preferably not less than8 mg, further preferably not less than 10 mg, further preferably notless than 15 mg, is provided. The ingestion amount of vitamin B6 permeal is generally less than 300 mg, preferably not more than 100 mg,since ingestion of an amount exceeding this level does not remarkablyenhance the anti-fatigue effect.

The anti-fatigue composition of the present invention can be provided asa food. In the present specification, food is a concept widelyencompassing oral ingestible matters, and includes not only what iscalled “food” but also a drink, health aid food, food with healthclaims, supplement, and the like. In the present invention, ananti-fatigue composition provided as food, food such as food in a unitpackage form per meal and the like, container-packed food, andcontainer-packed drink are sometimes to be generically referred to asthe food of the present invention. In addition, the anti-fatiguecomposition of the present invention can be provided as an agent. In thepresent specification, the agent excludes pharmaceutical products, andis ingested for a particular purpose, different from those dailyingested to retain nutrition of the body.

The form of the food of the present invention is not particularlylimited, and may be solid or semi-solid, or liquid m such as powder,tablet, granule, slurry, capsule, solution, jelly, emulsion, and thelike.

The form of histidine, and vitamin B6 and/or carnosine to be containedin the food of the present invention is not particularly limited, andmay be powder or granule, slurry, tablet confectionery, capsule,solution, jelly, or emulsion. Of these, granule and powder arepreferable, in view of easy portability and easy packaging. In addition,solution, jelly, and slurry are also preferable in view of easyingestion.

In the present invention, examples of the unit package form per mealinclude a form that defines a given amount in a pack, package, bottle,etc. in the case of drink, confectionery, jelly, pudding, yogurt, andthe like, and package and the like can define a given amount in the caseof granular, powdery and slurry foods. Alternatively, a form such as acontainer and the like indicating the ingestion amount per meal can bementioned. As used herein, confectionery refers to favorite foods suchas sweet stuff and the like, which are eaten other than meals, andexamples thereof include candy, chewing gum, tablet confectionery,chocolate, shake, ice, and the like.

The present invention provides a food comprising (1) histidine and (2)vitamin B6/or carnosine, which is in a unit package form per meal,particularly, a food comprising histidine and vitamin B6, which is in aunit package form per meal, and a food comprising histidine andcarnosine, which is in a unit package form per meal.

The food in a unit package form per meal of the present invention maycontain histidine and vitamin B6, or histidine and carnosine, orhistidine and vitamin B6, and carnosine. Preferred is one containinghistidine and vitamin B6.

The combination ratio of histidine and vitamin B6 can be appropriatelydetermined within the range where an anti-fatigue effect can beobtained.

Preferable combination ratios include histidine:vitamin B6=5:3 to 350:1,15:1 to 350:1, 30:1 to 350:1, 60:1 to 350:1, and 90:1 to 350:1. Otherpreferable combination ratios include histidine:vitamin B6=5:3 to 350:1,5:3 to 300:1, 5:3 to 240:1, and 5:3 to 120:1. Still other preferablecombination ratios include histidine:vitamin B6=5:3 to 350:1, 15:1 to300:1, 30:1 to 240:1, 60:1 to 120:1, and 90:1 to 120:1.

The combination ratio of histidine and carnosine can also be determinedappropriately within the range where an anti-fatigue effect can beobtained.

Preferable combination ratios include histidine:carnosine=1:4 to 100:1,1:2 to 100:1, and 1:1 to 100:1. Other 20 preferable combination ratiosinclude histidine:carnosine=1:4 to 100:1, 1:4 to 50:1, and 1:4 to 30:1.Other preferable combination ratios include histidine:carnosine=1:4 to100:1, 1:2 to 50:1, and 1:1 to 30:1.

When both vitamin B6 and carnosine are contained in addition tohistidine, the content of vitamin B6 and/or carnosine can be reduced ascompared to a single administration thereof.

As one embodiment of the food in a unit package form per meal of thepresent invention, a composition containing histidine:vitamin B6 at theabove-mentioned combination ratio, and histidine at not less than 0.3 g,preferably not less than 0.5 g, more preferably not less than 0.7 g,further preferably not less than 1 g, as an ingestion amount per meal isprovided. From the aspects of eating experiences obtained from knownfinding (mentioned above) and easiness of packaging and ingestion, theingestion amount per meal of histidine is preferably not more than 23 g,more preferably not more than 4 g. In the present invention, since theeffect of combined use of vitamin B6 on the anti-fatigue effect can beexpected, the ingestion amount per meal of histidine can be furtherreduced and, for example, a food containing not more than 3 g,preferably not more than 2 g, of histidine as an ingestion amount permeal can be provided.

In one embodiment of the food in a unit package form per io meal of thepresent invention, a food containing histidine:vitamin B6 at theabove-mentioned combination ratio, and histidine at not less than 0.3 g,preferably not less than 0.5 g, more preferably not less than 0.7 g,further preferably not less than 1 g, per unit package is provided.

In another embodiment of the food in a unit package form per meal of thepresent invention, a food containing histidine:vitamin B6 at theabove-mentioned combination ratio, and vitamin B6 at not less than 0.5mg, preferably not less than 2 mg, more preferably not less than 4 mg,further preferably not less than 6 mg, further preferably not less than8 mg, further preferably not less than 10 mg, further preferably notless than 15 mg, is provided. The ingestion amount of vitamin B6 permeal is generally less than 300 mg, preferably not more than 100 mg,since ingestion of an amount exceeding this level does not remarkablyenhance the anti-fatigue effect.

Another embodiment of the present invention is a container-packed food,comprising (1) histidine and (2) vitamin B6 and/or carnosine,particularly a container-packed food comprising histidine and vitaminB6, and a container-packed food comprising histidine and carnosine. The“food” in the container-packed food of the present invention is, forexample, the above-mentioned anti-fatigue composition provided as food.It can be produced by injecting or filling the food in a desiredcontainer.

The container-packed food of the present invention may contain histidineand vitamin B6, or histidine and carnosine, or histidine and vitamin B6and carnosine. Preferred is one containing histidine and vitamin B6. Thecombination ratio of histidine and vitamin B6 in the food can beappropriately determined within the range where an anti-fatigue effectcan be obtained.

Preferable combination ratios include histidine:vitamin B6=5:3 to 350:1,15:1 to 350:1, 30:1 to 350:1, 60:1 to 350:1, and 90:1 to 350:1. Otherpreferable combination ratios include histidine:vitamin B6=5:3 to 350:1,5:3 to 300:1, 5:3 to 240:1, and 5:3 to 120:1. Still other preferablecombination ratios include histidine:vitamin B6=5:3 to 350:1, 15:1 to300:1, 30:1 to 240:1, 60:1 to 120:1, and 90:1 to 120:1.

The combination ratio of histidine and carnosine can also be determinedappropriately within the range where an anti-fatigue effect can beobtained.

Preferable combination ratios include histidine:carnosine=1:4 to 100:1,1:2 to 100:1, and 1:1 to 100:1. Other preferable combination ratiosinclude histidine:carnosine=1:4 to 100:1, 1:4 to 50:1, and 1:4 to 30:1.Other preferable combination ratios include histidine:carnosine=1:4 to100:1, 1:2 to 50:1, and 1:1 to 30:1.

As one embodiment of the container-packed food of the present invention,a container-packed food containing histidine:vitamin B6 at theabove-mentioned combination ratio, and histidine at not less than 0.3 g,preferably not less than 0.5 g, more preferably not less than 0.7 g,further preferably not less than 1 g, as an ingestion amount per meal isprovided. From the aspects of eating experiences obtained from knownfinding (mentioned above) and easiness of packaging and ingestion, theingestion amount per meal of histidine is preferably not more than 23 g,more preferably not more than 4 g. In the present invention, since theeffect of combined use of vitamin B6 on the anti-fatigue effect can beexpected, the ingestion amount per meal of histidine can be furtherreduced and, for example, a container-packed food containing not morethan 3 g, preferably not more than 2 g, of histidine as an ingestionamount per meal can be provided.

In another embodiment of the container-packed food of the presentinvention, a container-packed food containing histidine:vitamin B6 atthe above-mentioned combination ratio, and vitamin B6 at not less than0.5 mg, preferably not less than 2 mg, more preferably not less than 4mg, further preferably not less than 6 mg, further preferably not lessthan 8 mg, further preferably not less than 10 mg, further preferablynot less than 15 mg, is provided. The ingestion amount of vitamin B6 permeal is generally less than 300 mg, preferably not more than 100 mg,since ingestion of an amount exceeding this level does not remarkablyenhance the anti-fatigue effect.

Another embodiment of the present invention is a container-packed drink,comprising (1) histidine and (2) vitamin B6 and/or carnosine,particularly a container-packed drink comprising histidine and vitaminB6, and a container-packed drink comprising histidine and carnosine. Thecontainer-packed drink of the present invention is one embodiment of theabove-mentioned container-packed food of the present invention. The“drink” in the container-packed drink of the present invention includes,for example, the above-mentioned anti-fatigue composition provided as adrink, specifically, drinks such as tea drinks (e.g., green tea, oolongtea, black tea, etc.), alcohol drinks (e.g., beer, wine, sake, distilledspirits, ume (Japanese plum) wine, low-malt beer, whiskey, brandy,etc.), beverage (e.g., sports drinks, isotonic drinks, mineral water,coffee drinks, etc.), juice (e.g., fruit juice, vegetable juice, etc.)and the like, liquid seasoning (e.g., soy sauce, vinegar, liquor, sweetsake for seasoning, soup stock, etc.), liquid supplement (e.g.,nutritional supplement drink, beauty drink, energy drink, etc.), and thelike. It can be produced by injecting or filling the drink in a desiredcontainer. The drink includes not only those served as a solution, asuspension and the like, but also those served for drinking afterextraction and dissolution such as tea leaves, coffee beans, powderdrinks, and the like.

The container-packed drink of the present invention may containhistidine and vitamin B6, or histidine and carnosine, or histidine andvitamin B6 and carnosine. Preferred is one containing histidine andvitamin B6. The combination ratio of histidine and vitamin B6 in thedrink can be appropriately determined within the range where ananti-fatigue effect can be obtained. Preferable combination ratiosinclude histidine:vitamin B6=5:3 to 350:1, 15:1 to 350:1, 30:1 to 350:1,60:1 to 350:1, and 90:1 to 350:1. Other preferable 15 combination ratiosinclude histidine:vitamin B6=5:3 to 350:1, 5:3 to 300:1, 5:3 to 240:1,and 5:3 to 120:1. Still other preferable combination ratios includehistidine:vitamin B6=5:3 to 350:1, 15:1 to 300:1, 30:1 to 240:1, 60:1 to120:1, and 90:1 to 120:1.

The combination ratio of histidine and carnosine can also be determinedappropriately within the range where an anti-fatigue effect can beobtained. Preferable combination ratios include histidine:carnosine=1:4to 100:1, 1:2 to 100:1, and 1:1 to 100:1. Other preferable combinationratios include histidine:carnosine=1:4 to 100:1, 1:4 to 50:1,and 1:4 to30:1. Other preferable combination ratios includehistidine:carnosine=1:4 to 100:1, 1:2 to 50:1, and 1:1 to 30:1.

As one embodiment of the container-packed drink of the presentinvention, a container-packed drink containing histidine:vitamin B6 atthe above-mentioned combination ratio, and histidine at not less than0.3 g, preferably not less than 0.5 g, more preferably not less than 0.7g, further preferably not less than 1 g, as an ingestion amount per mealis provided. From the aspects of eating experiences obtained from knownfinding (mentioned above) and easiness of packaging and ingestion, theingestion amount per meal of histidine is preferably not more than 23 g,more preferably not more than 4 g. In the present invention, since theeffect of combined use of vitamin B6 on the anti-fatigue effect can beexpected, the ingestion amount per meal of histidine can be furtherreduced and, for example, a container-packed drink containing not morethan 3 g, preferably not more than 2 g, of histidine as an ingestionamount per meal can be provided.

As one embodiment of the container-packed drink of the presentinvention, a drink containing histidine:vitamin B6 at theabove-mentioned combination ratio, and histidine at a concentration ofnot less than 1 w/v% can be ingested in necessary quantities fornecessary times. A container-packed drink preferably at not less than 3w/v%, more preferably not less than 5 w/v%, is provided. Acontainer-packed drink generally at not more than 30 w/v%, preferablynot more than 20 w/v%, more preferably not more than 17 w/v%, furtherpreferably not more than 10 w/v%, is provided.

In another embodiment of the container-packed drink of the presentinvention, a container-packed drink containing histidine:vitamin B6 atthe above-mentioned combination ratio, and vitamin B6 at not less than0.5 mg, preferably not less than 2 mg, more preferably not less than 4m, further preferably not less than 6 mg, further preferably not lessthan 8 mg, further preferably not less than 10 mg, further preferablynot less than 15 mg, is provided. The ingestion amount of vitamin B6 permeal is generally less than 300 mg, preferably not more than 100 mg,since ingestion of an amount exceeding this level does not remarkablyenhance the anti-fatigue effect.

A container to be used for the container-packed food or container-packeddrink of the present invention is appropriately selected according tothe object. Generally, a can, bottle, PET bottle, paper container,aluminum pouch, and the like can be mentioned. The volume is notparticularly limited, and one or more units may be housed in onecontainer wherein ingestion amount per meal is one unit, or concentratedfood/drink may be filled in a container.

The histidine, and vitamin B6 and/or carnosine contained in the food ofthe present invention being “slurry” means that solid histidine, andvitamin B6 and/or carnosine are suspended in a liquid medium. A part ofhistidine, and vitamin B6 and/or carnosine may be dissolved in theabove-mentioned medium.

In the food of the present invention, the ingestion form (1) histidineand (2) vitamin B6/or carnosine is not particularly limited, and (1) and(2) only need to be combined at the time of ingestion. Examples of suchadministration form include

(A) ingestion as a single food simultaneously containing (1) and (2),

(B) simultaneous ingestion of two kinds (or 3 kinds) of foods separatelycontaining (1) and (2) by the same administration route,

(C) ingestion of two kinds (or 3 kinds) of foods separately containing(1) and (2) by the same administration route in a staggered manner,

(D) simultaneous ingestion of two kinds (or 3 kinds) of foods separatelycontaining (1) and (2) by different administration routes,

(E) ingestion of two kinds (or 3 kinds) of foods separately containing(1) and (2) by different administration routes in a staggered manner,

and the like.

Examples of the application target of the food of the present inventioninclude experiment animals such as rodents (e.g., mouse, rat, hamster,guinea pig, and the like), rabbit and the like, pets such as a dog, cat,and the like, domestic animals and poultry such as bovine, swine, goat,horse, sheep, chicken, and the like, primates such as monkey, orangutan,chimpanzee, and the like, humans, and the like, and human isparticularly preferable. For application to an animal other than human,the dose of the food of the present invention can be appropriatelymoderated based on the general description of the dose for human, whichis described in the present specification, and further considering thebody weight or size of the animal, or the condition, sensitivity and thelike of the administration subject at the time of administration.

The food of the present invention is preferably food with health claims,more preferably food for improving fatigue.

The food of the present invention can contain various additives in anattempt to provide the same in a form easier to take. Specifically, acorrigent, flavor, excipient, lubricant, and the like can be mentioned,and any additive can be utilized as long as addition to food isadmitted. Examples of the corrigent include souring agents such asascorbic acid, tartaric acid, citric acid, malic acid and salts ofthese, and the like, sweeteners such as aspartame, stevia, sucralose,glycyrrhizinic acid, thaumatin, acesulfame potassium, saccharin,saccharin sodium and the like, and the like. Examples of the flavorinclude synthetic flavor compounds such as L-menthol and the like,citrus essential oils such as orange, lemon, lime, grapefruit, and thelike, plant essential oils such as a flower essential oil, peppermintoil, spearmint oil, spice oil, and the like, and the like. Examples ofthe excipient include lactose, sucrose, D-mannitol, starch, cornstarch,crystalline cellulose, light anhydrous silicic acid, and the like.Examples of the lubricant include magnesium stearate, calcium stearate,talc, colloidal silica, and the like.

Other features of the invention will become apparent in the course ofthe following descriptions of exemplary embodiments which are given forillustration of the invention and are not intended to be limitingthereof.

EXAMPLES Experimental Example 1 Verification of Influence of Burden ofInsufficient Sleep on Locomotor Activities in the Dark Phase (FatigueIndex)

Using CD2F1 mice (9-week-old or older) (CHARLES RIVER LABORATORIESJAPAN, INC) divided into a control group and a group burdened byinsufficient sleep, an experiment was performed as shown in theexperiment protocol of FIG. 1A.

The insufficient sleep-burdened group was burdened by insufficient sleepfor 24 hr by filling water in the breeding cage at the depth of 0.5 cm.The burden was released at 6 hr from the start of the light phase, andthe mice were placed back in the home cage and allowed to rest for 6 hr.The control group was reared without burden in the home cage.Thereafter, they were transferred into a cage set under a locomotoractivity measurement infrared sensor (Digital acquisition system;NS-DAS-32, Neuroscience Inc, Tokyo, Japan) under fasting andwater-deprivation. The locomotor activities in the former half (6 hr) ofthe dark phase were measured and the data was collected by amultidigital counter (Neuroscience Inc, Tokyo, Japan).

The results are shown in FIG. 1B. Since the insufficient sleep-burdenedgroup showed a decrease in the locomotor activities in the former halfof the dark phase (fatigue index) as compared to the control group, itwas clarified that burden of insufficient sleep decreases theperformance or induces fatigue.

Experimental Example 2 Verification of Influence of Burden ofInsufficient Sleep on Short-Working Memory (Fatigue Index)

Using CD2F1 mice (9-week-old or older) (CHARLES RIVER LABORATORIESJAPAN, INC) divided into a control group and an insufficientsleep-burdened group, an experiment was performed as shown in theexperiment protocol of FIG. 2A.

The insufficient sleep-burdened group was burdened by insufficient sleepfor 48 hr by filling water in the breeding cage at the depth of 0.5 cm.The burden was released 6 hr after the start of the light phase, and themice were placed back in the home cage and allowed to rest for 6 hr. Thecontrol group was reared without burden in the home cage. A Y-maze testwas performed at 3 hr from the start of the dark phase, andshort-working memory was measured.

The results are shown in FIG. 2B. Since the insufficient sleep-burdenedgroup showed a decrease in the short-working memory (fatigue index) ascompared to the control group, it was clarified that burden ofinsufficient sleep decreases the performance or induces fatigue.

Example 1 Verification of Effect of Administration of Histidine (His)and Test Substance X on Decrease in Locomotor Activities in the DarkPhase (Fatigue Index) After Burden of Insufficient Sleep

Using CD2F1 mice (9-week-old or older) (CHARLES RIVER LABORATORIESJAPAN, INC) in the group constitution shown in Table 1, the effect wasverified as shown in the experiment protocol of FIG. 3A.

TABLE 1 group No. group name His test substance X 1. solvent group − −2. His group + − 3. test substance X group − + 4. combined use group + +

The His group and the combined use group were allowed to drink eachsolution freely for one week so that the dose of His would be 500mg/kg/day. The test substance X group and the combined use group weremade to ingest test substance X mixed in a feed or drinking water forone week so that the ingestion amount of Table 3 would be met. As thefeed, a feed having the composition of Table 2 was used.

TABLE 2 Feed Composition composition composition (%) casein 20.0000L-cystine 0.3000 cornstarch 39.7486 pregelatinized cornstarch 13.2000sucrose 10.0000 soybean oil 7.0000 cellulose powder 5.0000 mineral mix(AIN-93G-MX) 3.5000 vitamin mix (AIN-93-MX) 1.0000 choline bitartrate0.2500 tertiary butylhydroquinone 0.0014

After ingestion of His and test substance X for one week, insufficientsleep was burdened for 24 hr by filling water in the breeding cage atthe depth of 0.5 cm. The burden was released at 6 hr from the start ofthe light phase, and the mice were placed back in the home cage andallowed to rest for 6 hr. Thereafter, they were transferred into a cageset under a locomotor activity measurement infrared sensor (Digitalacquisition system; NS-DAS-32, Neuroscience Inc, Tokyo, Japan) underfasting and water-deprivation. The locomotor activities in the formerhalf (6 hr) of the dark phase were measured and the data was collectedby a multidigital counter (Neuroscience Inc, Tokyo, Japan).

The results are shown in FIG. 3B. In the combined use group to which Hisand vitamin B6 (VB6) were given for one week, locomotor activities weresignificantly improved in the former half of the dark phase as comparedto the solvent group, and the locomotor activities tended to improve ascompared to the His ingestion group, it was clarified that the combineduse of His and vitamin B6 shows an anti-fatigue effect.

The combined use with carnosine was also examined in the same manner.The results are shown in FIG. 3C. It was clarified that the combined useof His and carnosine also shows an anti-fatigue effect. On the otherhand, other materials (7 materials) shown in Table 3 did not show ananti-fatigue effect whether each material was used alone or incombination with His.

TABLE 3 anti-fatigue effect ingestion 3. 4. test amount 2. test combinedsubstance X (mg/kg/day) His substance X use vitamin B12 6 x x x vitaminB1 50 x x x vitamin B6 300 x x ∘ DHA 700 x x x zinc 30 x x x creatine400 x x x L-carnitine 500 x x x α-glycero- 600 x x x phosphocholinecarnosine 1800 x x ∘

From the above results, it was clarified that a composition containinghistidine and vitamin B6 or carnosine has an anti-fatigue effect.

Example 2 Verification of Effect of Ingestion of the Present Invention(His:VB6=30:1) on Decrease in Short-Working Memory (Index of Fatigue)After Burden of Insufficient Sleep

Using CD2F1 mice (9-10-week-old) in the group constitution shown inTable 4, the test was performed as shown in the experiment protocol(FIG. 4A).

TABLE 4 free drinking ingestion dose group amount (mg/kg/day) (mg/kg)No. group name His VB6 His VB6 1. solvent group — — — — 2. His group 900— 900 — 3. VB6 group — 30 — 30 4. His + VB6 group 900 30 900 30

The His group and His+VB6 group were allowed to drink each solutionfreely for one week so that the ingestion amount of His would be 900mg/kg/day, and the ingestion amount of the VB6 group and the His+VB6group would be 30 mg/kg/day. As the feed, a feed having the compositionof Table 5 was used.

TABLE 5 component (%) feed composition amino acid mix 20.0000 L-cystine0.3000 cornstarch 39.7486 pregelatinized cornstarch 13.2000 sucrose10.0000 soybean oil 7.0000 cellulose powder 5.0000 AIN-93G mineral mix3.5000 AIN-93G vitamin mix 1.0000 choline bitartrate 0.2500 tertiarybutylhydroquinone 0.0014 composition of amino acid mix Ala 2.25 Arg 3.28Asn-H2O 3.60 Asp 3.16 Cys-Cys 0.50 Gln 12.04 Glu 9.16 Gly 1.62 His 0.51Ile 4.45 Leu 8.13 Lys-HCl 8.82 Met 2.43 Phe 4.50 Pro 9.37 Ser 5.06 Thr3.81 Trp 1.08 Tyr 4.85 Val 5.73 Starch 5.34

After ingestion of His or VB6, or both for one week, insufficient sleepwas burdened for 48 hr by filling water in the breeding cage at thedepth of 0.5 cm. The burden was released at 6 hr from the start of thelight phase, and the mice were placed back in the home cage and allowedto rest for 6 hr. Thereafter, the His group and His+VB6 group wereorally administered with His, and the VB6 group and His+VB6 group wereorally administered with VB6 at 2 hr from the start of the dark phaseafter burden of insufficient sleep to achieve the doses in Table 4. AY-maze test was performed at 3 hr from the start of the dark phase, andshort-working memory was measured.

The results are shown in FIG. 4B. After burden of insufficient sleepthat induces fatigue, the His+VB6 group showed a significant increase inthe alternation behavior as compared to the solvent group or His group.

From the above results, it was clarified that the composition of thepresent invention containing His:VB6=30:1 has an anti-fatigue effect.

Example 3 Verification of Effect of Ingestion of the Present Invention(His:VB6=120:1) on Decrease in Short-Working Memory (Index of Fatigue)After Burden of Insufficient Sleep.

Using CD2F1 mice (9-10-week-old) in the group is constitution shown inTable 6, the test was performed as shown in the experiment protocol(FIG. 5A).

TABLE 6 free drinking ingestion dose group amount (mg/kg/day) (mg/kg)No. group name His VB6 His VB6 1. solvent group — — — — 2. His group 900— 900 — 3. VB6 group — 7.5 — 7.5 4. His + VB6 group 900 7.5 900 7.5

The His group and His+VB6 group were allowed to drink each solutionfreely for one week so that the ingestion amount of His would be 900mg/kg/day, and the ingestion amount of the VB6 group and the His+VB6group would be 7.5 mg/kg/day. As the feed, a feed having the compositionof Table 5 was used.

After ingestion of His or VB6, or both for one week, insufficient sleepwas burdened for 48 hr by filling water in the breeding cage at thedepth of 0.5 cm. The burden was released at 6 hr from the start of thelight phase, and the mice were placed back in the home cage and allowedto rest for 6 hr. Thereafter, the His group and His+VB6 group wereorally administered with His, and the VB6 group and His+VB6 group wereorally administered with VB6 at 2 hr from the start of the dark phaseafter burden of insufficient sleep to achieve the doses in Table 6. AY-maze test was performed at 3 hr from the start of the dark phase, andshort-working memory was measured.

The results are shown in FIG. 5B. After burden of insufficient sleepthat induces fatigue, the His+VB6 group showed a significant increase inthe alternation behavior as compared to the solvent group or VB6 group,and an increase tendency in the alternation behavior as compared to theHis group.

Example 4

Verification of Effect of Ingestion of the Present Invention(His:VB6=120:1) on Locomotor Activities in the Dark is Phase (Index ofFatigue) After Burden of Insufficient Sleep

Using CD2F1 mice (9-10-week-old) in the group constitution shown inTable 6, the test was performed as shown in the experiment protocol(FIG. 6A).

The His group and His+VB6 group were allowed to drink each solutionfreely for one week so that the ingestion amount of His would be 900mg/kg/day, and the ingestion amount of the VB6 group and the His+VB6group would be 7.5 mg/kg/day. As the feed, a feed having the compositionof Table 5 was used.

After ingestion of His or VB6, or both for one week, insufficient sleepwas burdened for 24 hr by filling water in the breeding cage at thedepth of 0.5 cm. The burden was released at 6 hr from the start of thelight phase, and the mice were placed back in the home cage and allowedto rest for 6 hr. Thereafter, the His group and His+VB6 group wereorally administered with His, and the VB6 group and His+VB6 group wereorally administered with VB6 at 1 hr before the start of the dark phaseto achieve the doses in Table 6. The locomotor activities in the darkphase were measured by a multidigital counter (Neuroscience Inc., Tokyo,Japan).

The results are shown in FIG. 6B and FIG. 6C. At 4-5 hr after the startof the dark phase, the His+VB6 group showed a significant increase ascompared to the solvent group, and an increase tendency as compared tothe His group and the VB6 group.

From the results of Example 3 and Example 4, it was clarified that thecomposition of the present invention containing His:VB6=120:1 has ananti-fatigue effect.

Example 5 Verification of Effect of Ingestion of the Present Invention(His:VB6=360:1) on Decrease in Short-Working Memory (Index of Fatigue)After Burden of Insufficient Sleep

Using CD2F1 mice (10-21-week-old) in the group constitution shown inTable 7, the test was performed as shown in the experiment protocol(FIG. 7A).

TABLE 7 free drinking ingestion dose group amount (mg/kg/day) (mg/kg)No. group name His VB6 His VB6 1. solvent group — — — — 2. His group 900— 900 — 3. VB6 group — 2.5 — 2.5 4. His + VB6 group 900 2.5 900 2.5

The His group and His+VB6 group were allowed to drink each solutionfreely for one week so that the ingestion amount of His would be 900mg/kg/day, and the ingestion amount of the VB6 group and the His+VB6group would be 2.5 mg/kg/day. As the feed, a feed having the compositionof Table 5 was used.

After ingestion of His or VB6, or both for one week, insufficient sleepwas burdened for 48 hr by filling water in the breeding cage at thedepth of 0.5 cm. The burden was released at 6 hr from the start of thelight phase, and the mice were placed back in the home cage and allowedto rest for 6 hr. Thereafter, the His group and His+VB6 group wereorally administered with His, and the VB6 group and His+VB6 group wereorally administered with VB6 at 2 hr after the start of the doses inTable 7. A Y-maze test was performed at 3 hr from the start of the darkphase, and short-working memory was measured.

The results are shown in FIG. 7B. After burden of insufficient sleepthat induces fatigue, the His+VB6 group and His group showed asignificant increase in the alternation behavior as compared to the VB6group, but no group showed a significant increase as compared to thesolvent group.

Example 6 Verification of Effect of Ingestion of the Present Invention(His:VB6=360:1) on Locomotor Activities in the Dark Phase (Index ofFatigue) After Burden of Insufficient Sleep

Using CD2F1 mice (10-11-week-old) in the group constitution shown inTable 7, the test was performed as shown in the experiment protocol(FIG. 8A).

The His group and His+VB6 group were allowed to drink each solutionfreely for one week so that the ingestion amount of His would be 900mg/kg/day, and the ingestion amount of the VB6 group and the His+VB6group would be 2.5 mg/kg/day. As the feed, a feed having the compositionof Table 5 was used.

After ingestion of His or VB6, or both for one week, insufficient sleepwas burdened for 24 hr by filling water in the breeding cage at thedepth of 0.5 cm. The burden was released at 6 hr from the start of thelight phase, and the mice were placed back in the home cage and allowedto rest for 6 hr. Thereafter, the His group and His+VB6 group wereorally administered with His, and the VB6 group and His+VB6 group wereorally administered with VB6 at 1 hr before the start of the dark phaseto achieve the doses in Table 7. The locomotor activities in the darkphase were measured by a multidigital counter (Neuroscience Inc., Tokyo,Japan).

The results are shown in FIG. 8B. No group showed a significant increasein the activities as compared to the solvent group.

Example 7 Verification of Effect of Ingestion of the Present Invention(His:VB6=300:1) on Decrease in Short-Working Memory (Index of Fatigue)After Burden of Insufficient Sleep

Using CD2F1 mice (10-21-week-old) in the group constitution shown inTable 8, the test was performed as shown in the experiment protocol(FIG. 11A).

TABLE 8 free drinking ingestion dose group amount (mg/kg/day) (mg/kg)No. group name His VB6 His VB6 1. solvent group — — — — 2. His group 900— 900 — 3. VB6 group — 3.0 — 3.0 4. His + VB6 group 900 3.0 900 3.0

The His group and His+VB6 group were allowed to drink each solutionfreely for one week so that the ingestion amount of His would be 900mg/kg/day, and the ingestion amount of the VB6 group and the His+VB6group would be 3.0 mg/kg/day. As the feed, a feed having the compositionof Table 5 was used.

After ingestion of His or VB6, or both for one week, insufficient sleepwas burdened for 48 hr by filling water in the breeding cage at thedepth of 0.5 cm. The burden was released at 6 hr from the start of thelight phase, and the mice were placed back in the home cage and allowedto rest for 6 hr. Thereafter, the His group and His+VB6 group wereorally administered with His, and the VB6 group and His+VB6 group wereorally administered with VB6 at 2 hr from the start of the dark phaseafter burden of insufficient sleep to achieve the doses in Table 8. AY-maze test was performed at 3 hr from the start of the dark phase, andshort-working memory was measured.

The results are shown in FIG. 11B. After burden of insufficient sleepthat induces fatigue, the His+VB6 group showed a significant increase inthe alternation behavior as compared to the solvent group.

Formulation Example 1 Histidine and Vitamin B6-Containing Tablet

A histidine and vitamin B6-containing tablet having the followingcombination is produced by tableting according to a conventional method.The tablet weight is 340 mg.

TABLE 9 each component combination ratio (%) L-histidine 76.048 starchsyrup of reduced malt sugar 11.812 cellulose 9.506 calcium stearate 2vitamin B6 0.634 total 100

Formulation Example 2 Histidine and Vitamin B6-Containing Solution

A histidine and vitamin B6-containing solution having the followingcombination is produced by a conventional method. The solution weight is30 g.

TABLE 10 each component combination ratio (%) L-histidine 5.333 vitaminB6 0.050 sweetener 4.000 erythritol 10.000 high-intensity sweetener0.013 citric acid 4.000 flavor 0.060 water 76.544 total 100.000

Formulation Example 3 Histidine and Vitamin B6-Containing Granules

Histidine and vitamin B6-containing granules having the followingcombination are produced by a conventional method. The volume is 2 g.

TABLE 11 each component combination ratio (%) L-histidine 80.000 vitaminB6 0.700 excipient 10.980 high-intensity sweetener 0.420 citric acid6.400 flavor 1.500 total 100.000

Formulation Example 4 Histidine and Vitamin B6-Containing Jelly

A histidine and vitamin B6-containing jelly having the followingcombination is produced by a conventional method. The weight is 100 g.

TABLE 12 each component combination ratio (%) L-histidine 1.600 vitaminB6 0.015 gellant 0.800 fruit juice 0.265 sweetener 2.500 high-intensitysweetener 0.023 citric acid 1.861 flavor 0.200 water 92.736

Reference Example 1 Verification of Effect of Histidine (His) Ingestionfor 14 Days in Males Feeling Decrease in the Quality of Sleep andFatigue

Twenty males of 45 years old to less than 65 years old, who receivedtotal evaluation of not less than 17 points in the “self-diagnosisfatigue questionnaire” (Fatigue Science Laboratory Inc.), felt decreasein the quality of sleep (generally PSQI≥6), and obtained fatigue factorT scores of not less than 60 points in POMS, performed in advance, wereselected, and randomly divided into 2 groups (10 per group). A crossovertest, including ingesting histidine and control food (equal volume ofcellulose) each for 14 days, was performed in each group.

As shown in the experiment protocol of FIG. 9A, the test subjectsingested capsules containing 1.65 g of L-histidine as a daily ingestionamount (5 capsules (hard capsule #2 WHITE OP B/C) containing 0.33 g ofL-histidine alone), or control sample capsules (5 capsules containingequal volume of cellulose) for 14 days. After the completion of 14 dayingestion, a 14 day resting period was taken. After the resting period,they ingested the capsules not ingested before the resting period.

On the initial day and the day after completion of the capsule ingestionperiod, the test subjects answered POMS and the VAS questionnaires(fatigue, depression, vague sense, drowsiness, clear thinking,motivation, attentiveness, concentration) relating to fatigue, andcognitive function measurement task CogHealth (under higher difficultyconditions by simultaneously including mental arithmetic task as well)to measure intellectual performance which is one of the fatigue indices.Furthermore, they answered VAS questionnaires after completion ofCogHealth. Evaluation after completion of CogHealth reveals thedifferency of the state between after and before the work-load.

The results are shown in FIGS. 9B to 9E. As compared to the testsubjects who ingested the control food, the fatigue factor scores ofPOMS significantly decreased (paired t-test: p<0.05) (FIG. 9B) and thesense of clear thinking, motivation, and attentiveness significantlyincreased (paired t-test: p<0.05) in VAS questionnaires relating tofatigue (FIG. 9C) in the test subjects who ingested histidine for 14days. In the intellectual work efficiency, ingestion of histidineshortened the reaction time of cognitive function measurement task andsignificantly decreased the reaction time of delayed recall task (pairedt-test: p<0.05) as compared to ingestion of the control food (FIG. 9D).In VAS questionnaires after completion of CogHealth, moreover, the senseof depression significantly decreased and the sense of motivation andattentiveness significantly increased (paired t-test: p<0.05) (FIG. 9E).This means that an increase in motivation and attentiveness can bemaintained, and feeling of depression by burden can be suppressed, evenwhen cognitive work is loaded.

From the above results, it was clarified that an agent containinghistidine can improve/recover fatigue.

Reference Example 2 Verification of Effect of Single Histidine (His)Ingestion in Males Feeling Decrease in the Quality of Sleep and Fatigue

Twenty males of 45 years old to less than 65 years old, who receivedtotal evaluation of not less than 17 points in the “self-diagnosisfatigue questionnaire” (Fatigue Science Laboratory Inc.), felt decreasein the quality of sleep (generally PSQI≥6), and obtained fatigue factorT scores of not less than 60 points in POMS performed in advance, wereselected, and randomly divided into 2 groups (10 per group). The effectof single ingestion of histidine and control food (equal volume ofcellulose) was compared in each group.

As shown in the experiment protocol of FIG. 10A, the test subjects tookthe same meals for 3 days before the experiment, fasted for 10 to for 14hr, and ingested capsules containing 1.65 g of L-histidine as a singleingestion amount (5 capsules (hard capsule #2 WHITE OP B/C) containing0.33 g of L-histidine alone), or control sample capsules (5 capsulescontaining equal volume of cellulose).

Before and 1 hr after ingestion of capsules, the test subjects answeredthe VAS questionnaires (fatigue, depression, vague sense, drowsiness,clear thinking, motivation, attentiveness, concentration) relating tofatigue, and cognitive function measurement task CogHealth (under higherdifficulty conditions by simultaneously including mental arithmetic taskas well) to measure intellectual performance which is one of the fatigueindices. Furthermore, they answered VAS questionnaires after completionof CogHealth. Evaluation after completion of CogHealth reveals thedefferency of the state between after and before the work-load.

The results are shown in FIGS. 10B and 10C. It was found that the worktime in 5 kinds of brain function measurement indices was shortened inthe test subjects who ingested histidine, as compared to the testsubjects who ingested the control food. In VAS questionnaires relatingto fatigue, the sense of clear thinking and attentiveness significantlyincreased and the sense of concentration tended to increase (pairedt-test: p<0.05) (FIG. 10B). In VAS questionnaires after completion ofCogHealth, moreover, the sense of vague sense significantly decreased,the sense of depression tended to decrease, and the sense ofconcentration tended to increase (paired t-test: p<0.05) (FIG. 10C).This means that ingestion of histidine may be able to suppress vaguesense and the sense of depression due to burden and maintainconcentration, even when cognitive work is loaded.

From the above results, it was clarified that an agent containinghistidine can improve/recover fatigue.

As mentioned above, continuous ingestion of histidine for 2 weeks showedimprovement/recovery of fatigue, and a single ingestion of His showedimprovement/recovery of fatigue. Ingestion of His did not showproblematic variation in general properties, hematology, and bloodbiochemistry from the aspects of safety.

INDUSTRIAL APPLICABILITY

Fatigue (mental fatigue, physical fatigue) can be improved by ingestingthe composition of the present invention comprising (1) histidine and(2) vitamin B6 and/or carnosine. Since the active ingredients thereofare amino acid (peptide) and vitamin, the present invention has lessfear of causing side effects, is superior in safety, and can beconsecutively used every day.

Where a numerical limit or range is stated herein, the endpoints areincluded. Also, all values and subranges within a numerical limit orrange are specifically included as if explicitly written out.

As used herein the words “a” and “an” and the like carry the meaning of“one or more.”

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

All patents and other references mentioned above are incorporated infull herein by this reference, the same as if set forth at length.

1. An anti-fatigue composition, comprising (1) histidine and (2) vitaminB6 and/or carnosine in combination. 2-44. (canceled)